Factors affecting the growth of Eucalyptus delegatensis seedlings in inhibitory forest and grassland soils
- 141 Downloads
In many highland forests of Eucalyptus delegatensis in Tasmania the establishment and healthy growth of eucalypts is promoted and maintained by fire. In the absence of fire, secondary succession from eucalypt forest to rainforest occurs, during which the eucalypts decline and die prematurely. On sites that are prone to radiation frost severe reduction or removal of a tree canopy allows a sward of tussock grasses to develop, in competition with which seedlings of eucalypts decline in growth and a high proportion dies.
a secondary succession of vegetative types from recently burned healthy eucalypt forest to unburned mature rainforest: this encompassed a sequence of decline and death of the eucalypt trees;
soil from old grassland in which eucalypt seedlings were exhibiting severe growth check and mortality;
from beneath individual trees of several species growing on old grassland.
Growth of seedlings in untreated pot soil reflected closely the condition of eucalypt trees in the field in that growth declined through the successional sequence to rainforest; it was very poor in soil from old grassland; and it varied markedly among soils from beneath different tree species and phases of the grassland. Mycorrhizal development on the pot seedlings differed among soils in both forms and associated fungal types.
Poor growth was overcome only partially by either addition of N and P fertilisers or by partial sterilisation of soil by using steam or chemicals. Inoculation of inhibitory soil from both secondary rainforest and old grassland with 10% to 20% of soil from a healthy eucalypt stand overcame inhibition completely in each case. It is concluded that changes in soil microbiological factors, and specifically in mycorrhizal associations, that accompany changes in vegetative components of the eucalypt stands could be the principal cause of both dieback of older trees and growth check of seedlings.
Key wordsEucalyptus forest soils grassland soils mycorrhizas plant nutrition soil fumigation
Unable to display preview. Download preview PDF.
- Ashton D H and Willis E J 1982 Antagonisms in the regeneration of Eucalyptus regnans in the mature forest. Blackwell Scientific Series: Special publication of the British Ecological Society 1.Google Scholar
- Blasius, D and Oberwinkler, F 1989 Succession of mycorrhizae: A matter of tree age or stand age? In Ann. Sci. For. 46 suppl, pp 758–761 of Forest Tree Physiology. Eds. EDreyer, GAussenac, MBonnet-Masimbert, PDizenzremel, J MFavre, J PGarrec, F, Le Tacon and F.Martin. Elsevier, Paris, France.Google Scholar
- Dighton, J and Mason, P A 1985 Mycorrhizal dynamics during forest tree development. In Developmental Biology of Higher Fungi. Eds. DMoore, L ACasselton, D AWood and J CFrankland. pp 117–139. British Mycological Society Symposium 10. Cambridge University Press. Cambridge.Google Scholar
- Duff, G A and Stocker, G C 1989 The effects of frosts on rainforest/open forest ecotones in the highlands of North Queensland. Proc. R. Soc. Qd 100, 49–54.Google Scholar
- Ellis, R C 1964 Dieback of alpine ash in North eastern Tasmania. Aust. For. 28, 75–90.Google Scholar
- Ellis, R C 1971 Dieback of Alpine Ash as related to changes in soil temperature. Aust. For. 35, 152–163.Google Scholar
- Ellis, R C, Mount, A B and Mattay, J P 1980 Recovery of Eucalyptus delegatensis from high altitude dieback after felling and burning the understory. Aust. For. 43, 29–35.Google Scholar
- Ellis, R C 1985 The relationships amongst eucalypt forest, grassland and rainforest in a highland area in Northeastern Tasmania. Aust. J. Ecol. 12, 307–317.Google Scholar
- Ellis, R C and Graley, A M 1987 Soil chemical properties as related to forest succession in a highland area in Northeastern Tasmania. Aust. J. Ecol. 12, 307–317.Google Scholar
- Florence, R G and Crocker, R L 1962 Analysis of blackbutt (Eucalyptus pilularis Sm.) seedling growth in a blackbutt forest soil. Ecology 43, 670–679.Google Scholar
- Hamilton C D 1972 The nature and causes of spatial variation in forest ecosystems. Ph.D. Thesis Australian National University, Canberra.Google Scholar
- Harwood C E 1976 Ecological studies of timberline phenomena. Ph.D. Thesis Australian National University, Canberra.Google Scholar
- Ingestad, T and Kahr, M 1985 Nutrition and growth of coniferous seedlings at varied relative introgen addition rate. Physiol. Plant. 65, 109–116.Google Scholar
- Keenan, R J and Candy, S 1983 Growth of young Eucalyptus delegatensis in relation to variation in site factors. Aust. For. Res. 13, 197–205.Google Scholar
- Moore, R M and Williams, J D 1976 A study of a sub-alpine woodland-grassland boundary. Aust. J. Ecol. 1, 145–153.Google Scholar
- Muller, C H 1966 The role of chemical inhibition (allelopathy) in vegetative composition. Bull. Torrey Bot. Club 93, 332–351.Google Scholar
- Ryan, P J and McGarity, J W 1983 The nature and spatial variability of soil properties adjacent to large forest eucalypts. Soil Sci. Soc. Am. J. 47, 286–292.Google Scholar
- Unwin, G L, Stocker, G C and Sanderson, K D 1985 Fire and the forest ecotone in the Herberton highland, Nth Queensland. Proc. Ecol. Soc. Aust. 13, 215–224.Google Scholar
- Warcup, J H 1991 The fungi forming mycorrhizae on eucalypt seedlings in regeneration coupes in Tasmania. Mycol. Res. 95, 329–332.Google Scholar
- Watt, A S 1947 Pattern and process in the plant community J. Ecol. 45, 159–162.Google Scholar
- White, D P 1941 Prairie soil as a medium for tree growth. Ecology 22, 398–407.Google Scholar